Anyone planning to look up Paul Revere's birthday on Wikipedia or scan Reddit for cute photos of baby dolphins will be out of luck Wednesday.

The English version of Wikipedia — the popular, collaborative online dictionary — will go black for 24 hours Wednesday, and social news sharing site Reddit will shut down for 12 hours as part of an online protest against anti-piracy legislation under consideration in Congress.

"We believe in a free and open Internet where information can be shared without impediment," Sue Gardner, Wikimedia Foundation's executive director, wrote in a blog post Monday. "We believe that new proposed laws ... and other similar laws under discussion inside and outside the United States, don't advance the interests of the general public."

The Stop Online Piracy Act, or SOPA, in the U.S. House of Representatives, and the Protect Intellectual Property Act, or PIPA, under consideration in the U.S. Senate, are designed to crack down on sales of pirated U.S. products overseas.

Supporters including the film and music industries — which often see their products sold illegally — predict the legislation will protect intellectual property and jobs.

Critics say the bills could hurt the technology industry and infringe on free-speech rights. Among their concerns are provisions that would weaken cyber-security for companies and hinder domain access rights.

The most controversial provision is in the House bill, which would have enabled federal authorities to "blacklist" sites that allegedly distribute pirated content, essentially cutting off portions of the Internet to all U.S. users. However, congressional leaders appear to be backing off that provision.

A number of tech companies such as Google, Facebook, Yahoo, Twitter, eBay and AOL have spoken out against the legislation, saying it threatens the industry's livelihood. Google says it won't participate in Wednesday's blackout but will link to information about the legislation on its home page, according to reports.

"Like many businesses, entrepreneurs and web users, we oppose these bills because there are smart, targeted ways to shut down foreign rogue websites without asking American companies to censor the Internet," Google told popular technology blog Mashable in a statement.

Twitter CEO and Corte Madera resident Dick Costolo defended his company's decision not to participate in the blackout.

"Closing a global business in reaction to single-issue national politics is foolish," Costolo said Monday in a Twitter post.

San Rafael-based Autodesk, which makes AutoCAD, Maya and Inventor engineering and design software among other offerings, acknowledged it loses "millions of dollars every year to software piracy" primarily outside the United States — but said it opposes the current legislation.

"Autodesk applauds Congress for recognizing the threat that software piracy poses to our economy, but we cannot support SOPA as written," spokesman Greg Eden said.

In a statement released Tuesday, Chris Dodd — a former U.S. senator and current chairman and CEO of the Motion Picture Association of America — called Wednesday's blackout "yet another gimmick ... designed to punish elected and administration officials who are working diligently to protect American jobs from foreign criminals.

"It is an irresponsible response and a disservice to people who rely on (the websites) for information and use their services," Dodd said. "It is also an abuse of power given the freedoms these companies enjoy in the marketplace today."

Rep. Lynn Woolsey, D-Petaluma, hasn't decided yet whether she will support the legislation, in part because the bill has continued to evolve in the House, her spokesman said.

Over the weekend the Obama administration raised concerns about the legislation and said it will work with Congress to help battle piracy and counterfeiting while defending free expression, privacy, security and innovation on the Internet.

The American Library Association and Library Copyright Alliance have also expressed worries about the legislation, predicting it could leave libraries vulnerable to copyright liability, threaten privacy and erode free speech.

Sarah Houghton, acting director of the San Rafael Public Library and author of the "Librarian in Black" blog, said many librarians are also concerned about access to online databases and electronic books. Patrons generally submit their library identification number and PIN to access those materials and the library verifies that data before passing it on to a third party, she said.

"The way that most libraries do that could be considered in violation of both SOPA and PIPA," Houghton said. "It's a very vague way that they define a lot of this 'naughty' behavior. As a result it would be very easy for us as libraries to violate it without even intending to.

"Anything that blocks the legal sharing of information is bad to libraries, and the way that the bills are written, because they are so vague, could very easily block the legal sharing of information," she added.

This is the first time Wikipedia's English version has gone dark. Its Italian site came down once briefly to protest an Internet censorship bill, which the Berlusconi government put forward. That bill ultimately did not advance.